GOES-R Goes Up: How New Technology Is Changing Weather Forecasting
By Hilary E. Snell
In the world of satellite technology, what goes up also tends to stay up—although next-generation advances are now sending key information about severe storms back down. That satellite, known as GOES-R, is bringing sharper insights about lightning and other factors that shed light on the timing, track, and intensity of storms. But what goes into a forecast, and how do forecasters predict the weather? In preparation for GOES-R, AER has been working for the last seven years on technology designed to improve forecasting substantially for decades to come.
Many people know that weather forecasts are based on computer models. The models themselves start with data describing the current atmospheric state, information routinely gathered from surface observations, weather balloons, and satellites. Two key satellites in this process of predicting the weather over the Americas are GOES-13 (GOES-East) and GOES-15 (GOES-West), operated by the National Oceanographic and Atmospheric Administration (NOAA). The observations from these satellites represent critical information used by a diverse set of national and international weather forecast centers.
History, in orbit
GOES stands for Geostationary Operational Environmental Satellite. Geostationary means that it orbits Earth at the same rate Earth rotates around its own axis, so it appears to be always located above a fixed point on the ground along Earth’s equator. The GOES program started with GOES-1, launched on October 16, 1975. GOES-East is located over the equator at a longitude of 75 degrees west. It’s able to view the East Coast and much of the Midwest and monitor the tropical Atlantic regions that generate many hurricanes. The other, GOES-West, is located at 135 degrees west to view the western states out into the Pacific Ocean, tracking the powerful Pacific storms that regularly affect the West Coast.
The latest satellite in the series, GOES-R, launched on November 19, 2016. The “R” stands for R-series, which represents the newest set of technology. Once in orbit, it will be renamed GOES-16. A GOES satellite consists of a number of different types of sensors designed to measure various geophysical properties of the atmosphere and space. The advanced instrumentation developed for GOES-R will significantly increase the timeliness, accuracy, and reliability of those measurements. Improved information about clouds and wind from the Advanced Baseline Imager (ABI), a sophisticated camera that records both visible and infrared images, will improve short-term weather forecasts.
Recording the flash
The Global Lightning Mapper (GLM), a new type of camera designed specifically to record lightning flashes, will continuously measure lightning activity (in-cloud, cloud-to-cloud, and cloud-to-ground), a key indicator of severe storm formation and the first-ever continuous, hemispheric-wide measurement of lightning. Together, the improved measurements from ABI and GLM will increase the warning lead time for severe thunderstorms and tornadoes and provide improved hurricane tracking and intensity forecasts. Additional sensors will provide information about solar flares and the near-space environment, leading to warnings about radio communication and GPS outages.
AER’s contributions to satellite remote sensing expertise started more than 35 years ago. In 2003, AER began preparing for GOES-R and carried out several government-sponsored concept studies to help shape the future measurement and performance requirements for the satellite. Once NOAA finalized the specifications, separate proposals were requested to build each of the instruments, the satellite itself, and the ground satellite control and data processing system. AER joined a team formed by Harris Corporation to provide a state-of-the-art solution to meet NOAA’s needs for decades to come. In May 2009, after two years of proposal preparation—including intensive written questions and an oral exam—the Harris team was selected by NOAA as the winner for the ground system development, responsible for the satellite control, instrument data processing, and data distribution.
Insights from above
AER’s role in GOES-R has been to develop the operational software that converts raw instrument measurements into geophysical parameters, including cloud cover, lightning, and sea surface temperature maps; characterization of wildfires; atmospheric temperature and humidity profiles; and space weather measurements such as the solar X-ray flux. Program success required AER to establish two key customer collaborations. First, AER worked closely with government scientists to translate algorithms developed by government and university researchers into high-quality operational software. (An algorithm, in this case, is the recipe for converting the sensor measurements into geophysical quantities such as cloud type, lightning strikes, and solar flare information.)
Along the way, AER used its scientific expertise to understand the algorithms and develop the data necessary to fully test the software before delivery to Harris. The second collaboration was with the Harris Corporation to integrate and optimize the software into the operational Product Generation System. AER did this to meet the high-availability (up time is better than 99.99 percent) and high-throughput/low-latency requirements, because the amount of data that GOES-R records is increased by more than a factor of 60 from previous satellites. An innovative software product, the AER Algorithm Workbench, was used to support both functions.
As a result of the collaborations, all the AER-developed software, representing more than 450,000 logical lines of code, was installed and tested in the ground-processing system and delivered to NOAA by May 2015. Since that time, AER has continued testing the software and working diligently to ensure the new system is ready for “live data.” AER has also been preparing plans and procedures for the postlaunch test phase of the project, which should last about six months.
Future of weather forecasting
So how will GOES-R affect you? There may soon be more accurate weather forecasts. Sometime in 2017, AER expects the validated GOES-R data to begin flowing to weather models and forecasters. The improved resolution and higher refresh rate of the GOES-R imagery (every five minutes or less) should immediately become apparent, providing a smoother and more revealing depiction of the weather. Look for these images in weather reports sometime next year. Somewhat subtler will be improvements in weather forecasts, which depend on the GOES-R data. Over time, the higher-quality, higher-resolution GOES-R data products are expected to provide improvements in accuracy and lead times for forecasts of critical weather phenomena, which are intended to affect public safety, industry, transportation, and agriculture.
GOES-R has been an exciting project for AER that has united people with different scientific and software skill sets into a cohesive team focused on the goal of having a ground system ready for launch. What started with a handful of scientists and engineers working the initial concept studies evolved into, at its peak, an integrated team of more than 60 scientists and software engineers working from AER’s headquarters in Lexington, Massachusetts, and a customer facility in Greenbelt, Maryland. The GOES-R series of satellites—which includes GOES-S, GOES-T, and GOES-U—is scheduled to provide the backbone of NOAA’s geostationary environmental data until 2036.
This image shows the volume of liquid water and ice in clouds using the current GOES-13 data. This data is updated every 15 minutes. GOES-R will provide higher spatial and temporal resolution imagery, resulting in a better understanding of storm formation and dynamics.
The version below shows Hurricanes Matthew and Nicole.